Stretched cable membrane attachment system

ABSTRACT

In standard single ply membrane roofing, there is a great number of fasteners used. If the roof deck does not accept standard mechanical fasteners, the workload required to mechanically fasten a roof becomes quite immense. The stretched cable membrane attachment system is designed to improve efficiency in installing single ply roofing membrane, as well as improve wind uplift resistance for the roofing system. It consists of a cable that is attached at both ends to the roof substrate or decking and is then sealed from the elements by means of placing additional membrane over it and adhering it to the already installed membrane. One embodiment of the device has the means of installing a turn buckle to increase the cable tension or has the turn buckle as part of its integral design. In another embodiment, the cable can have multiple mechanical fastening points on the interior of its structure in addition to the endpoints.

CROSS REFERENCE TO RELATED APPLICATIONS

This invention is based upon and claims the benefit of priority fromU.S. Provisional Application Ser. No. 60/934,747 filed the 15 of Jun.,2007.

INTRODUCTION

The title of the invention set forth in this document is “StretchedCable Membrane Attachment System.” The inventor's name is Henry L.Hamlin III, residing in Macon, Ga. and with United States citizenship.The inventor's correspondence address is PO Box 7548, Macon, Ga. 31209.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTINGCOMPACT DISK APPENDIX

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and system of installingroofing membrane, particularly installation by use of a stretched cableand appropriate fasteners in place of standard screws and otherfasteners.

2. Background

A typical single ply membrane roofing system for a low slope roofincorporates several different primary features. The deck is typicallymade of one of three materials: metal, wood, or concrete. Over the deckthere is a layer of insulation and over the layer of insulation is asheet of roofing membrane. The make up of a typical roof may vary butthe one described is the most common method. There are multiple ways offastening the materials to the deck but the prevailing method is tomechanically fasten. This method is cost efficient and saves on laborversus other methods such as fully adhering (whereas the entire membraneis effectively glued to the substrate beneath).

In the case of a metal or wood deck, fastening of the insulation andmembrane is quite simple. One typically uses roofing screws that arelong enough to penetrate to the decking with a circular stress platesituated beneath and centered around the head of the screw. Both theinsulation and the membrane are fastened in this manner with fastenersthat are similar. For the membrane, there is a specified number offasteners per a specified length of membrane (typically spaced betweenevery six inches to every twenty four inches linearly, dependant onfactors such as the width of the roll of membrane and wind upliftrequirements). For the insulation, there is typically a set number offasteners per piece (dependant on the size of the insulation board).Over the areas where the membrane is fastened down to the deck, the nextlayer of membrane is overlapped onto the existing, thereby going overthe existing set of fasteners and covering them with membrane. Thisoverlapping membrane is then heat-welded or adhered to the existinglayer beneath it. The entire roof is typically covered with membrane inthis fashion.

At walls, flat perimeters, and various penetrations through the roof,the membrane must be terminated and waterproofed so as to preventleakage and to fully secure the membrane. Typically, this is done withtermination bar, a bar that is situated on top of the membrane andfasteners are placed through the bar, the membrane and on through to thesubstrate. Appropriate sealants are then used to seal up seams andvertical junctures so as to prevent water from reaching underneath themembrane.

The primary difficulty with mechanical fastening occurs when there is atype of deck that is considered non-nailable. The primary type ofnon-nailable deck is the concrete deck. In order to mechanically fastento a concrete deck, a hole must first be pre-drilled and then a specialtype of fastener is inserted and attached. Whereas fastening a screwinto a metal deck is a simple process, fastening into a concrete deck isa multi-step process and takes up considerably more time and is muchmore expensive. Since the same number of fasteners is typically requiredas with a nailable deck, the process tends to take much longer for theconcrete, in turn increasing the total cost for the roof to be completedin both materials and labor.

There have been previous inventions that have attempted to solve thisproblem. One of interest would be U.S. Pat. No. 7,028,438, which is aroofing system that utilizes hold down straps for the insulation. Inaddition, others have used batten bars, which help to further secure theroofing membrane in locations of the membrane that are linearly betweenfasteners. U.S. Pat. No. 6,764,260 uses this method. These prior methodsfail to sufficiently improve the process of mechanically fastening to anon-nailable deck.

SUMMARY OF THE INVENTION

The goal of this invention is to improve the efficiency of attachingsingle ply membranes to roof decks, as well as to improve wind upliftresistance and durability of the membrane roof in general. The stretchedcable membrane attachment system is designed around the concept of usinga cable to secure the roof membrane to the deck. In its ideal form, thecable would have multiple fasteners that are further apart than onewould normally space them but of sufficient spacing to provide theappropriate fastening strength. The cable would be fastened down to theroof deck and then the next roll of membrane would be heat welded overthe fasteners and cable to the existing layer of membrane, thus sealingin the fasteners. The reason the fasteners could be spaced further apartis that the cable itself would provide additional holding strength inbetween the fastener locations without having to go through the extraeffort and complications of using additional fasteners.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial view of one possible embodiment of the cable (1)fitted with multiple fastening points (2).

FIG. 2 is a partial view of one possible embodiment showing the cable(1) fitted with a turn buckle (3). This figure also depicts the primaryparts of the turn buckle (3): the main body (4), the threaded rods (5),and the fastening points (2).

FIG. 3 is a side cutout view of the cable system in use on the perimeterof a flat roof. The cable (1) is depicted with a mechanical fastener (8)extending through the fastening point (2) of the cable (1). The membrane(6) is situated on top of the roof substrate (7). The cable (1) isfastened on top of the membrane (6) then the excess portion of themembrane (10) is folded up back in the direction of the roof and adheredor thermally welded to that membrane (6) which is already fastened.

FIG. 4 is a side cutout view of the cable system in an alternate usage,in use on the main section of the flat roof where the membrane seamsmeet. The cable (1) is depicted with a mechanical fastener (8) extendingthrough the fastening point (2) of the cable (1). The cable (1) issituated on the seam of one layer of membrane (11), thus fastening itinto the substrate (7). The second layer of membrane (12) is laid overthe cable (1) and heat welded or adhered to the already fastened layerof membrane (11), thus securing the roof to the substrate (7), as wellas covering the cable (1), fasteners (8), and fastening points (2) fromthe elements.

FIG. 5 is a top view of a layout of the cable system as it could be usedboth on the perimeters of a flat roof, as well as on the interior.Ultimately, the cable (1) would not be visible as it would be covered bya layer of membrane but this possible layout is depicted in order toshow one possible method of installation, as well as the versatility ofthe system. The cable system depicted has multiple fastening points (2)on each cable. The cable (1) depicted is outfitted with turn buckles (3)on each cable (1) as well.

DETAILED DESCRIPTION OF THE INVENTION

The roofing system that this patent application is proposing is the useof a stretched reinforced cable in mechanically fastened membraneroofing systems. The cable would be of a type with tensile strength suchthat it could be tightened and be capable of withstanding wind upliftand movement of the building due to temperature changes and otherenvironmental factors. The cable would be fastened at its appropriatefastening points and then another layer of membrane, either from thevery same roll of material or from the subsequent roll that would beused, would be placed over the cable and fasteners then heat welded oradhered to the material on the other side of the cable. This wouldeffectively seal in the cable and all its parts within the membrane,thus protecting it from the outside elements.

One feature of the stretched cable membrane attachment system would bethat each cable could include multiple fastening locations in additionto the fasteners at the ends of the cable. These additional fasteninglocations could be spaced throughout the length of the cable at spacingsappropriate to the particular roofing application and the materialsinvolved. These fastening points would not have to be as close as thespacings one would use if only using fasteners due to the presence ofthe cable between the fasteners helping to hold the roof securely to thebuilding. In these fastening points, mechanical fasteners could beinserted and the cable could be attached to the roof deck. The fastenersused could be standard mechanical fasteners with the type dependant onthe type of roof deck as well as the particular building andapplication.

The distance apart of each of the interior fastening points would bedetermined by the size of the roof for which it would be used, as wellas the particular type of materials used. For smaller roofs, it mightnot be necessary to fasten at any interior point, only at the endpointsof the cable. Larger roofs' fastening requirements might necessitate amuch greater number of fasteners.

The stretched cable membrane attachment system could have at someinterior point within its length a turn buckle that would be used totighten the cable prior to fastening any existing interior fasteningpoints and after fastening the two end fastening points. For field use,the cable could be manufactured such that it had multiple fasteningpoints at particular spacings. One would cut the cable for roofinstallation such that each cut piece had one end with a fastening pointand one end without a fastening point (and multiple points within itslength). Therefore, the end without a fastening point would be placed inthe turn buckle and the other end would serve as an endpoint for thecable to be installed. Another piece of cable could be cut and one ofits ends placed in the other end of the turn buckle, thus making asingle cable with two fastening endpoints, interior fastening points,and a turn buckle at some point along its length. The length of thecable, as well as the tightness of the cable, could then be fine tunedby turning the turn buckle to an appropriate tightness. Tightness of thecable would be determined by several factors, including the wind upliftresistance desired, the size of the roof, and thermal or otherenvironmental movements that might be expected from the building inquestion.

There are multiple methods of using the stretched cable membraneattachment system. One way is to lay out membrane over the entire roofand seal its seams together by the appropriate method (typicallyadhering with some type of mastic or heat welding). One would leaveexcess materials at the perimeter of the roof. Next, one would installthe cable at all perimeters of the roof then fold the excess membraneover the cable and adhere the upper layer of the excess membrane to theupper layer of the installed membrane, thus sealing in the cable. Ifcables were needed for fastening within the perimeter of the roof, onecould attach the cable and tighten it if needed then adhere a layer ofmembrane over the cable. The additional layer of membrane would then beadhered all around the cable to the installed membrane already on theroof, thus sealing the cable in the membrane.

An alternate method of installation would be to fold the membrane at theseams over the cable. After the cable is fastened and, if necessary,tightened, there exists a layer of excess membrane that extends past thepoint at which the cable is fastened. This excess membrane would befolded over the cable and welded (either by heat or other means ofadherence) to the secured membrane on the roof. The entire cable wouldbe sealed in this manner from end to end. This procedure would seal thecable entirely in membrane, thus waterproofing it and protecting boththe fasteners and the cable from the elements with minimal seams,fastening points, and other areas of potential leakage.

It is also possible for the membrane itself to be manufactured with thecable already sealed up within it along one side of its seams. Therewould have to holes through which the fasteners could pass, though thesewould be covered up when the next roll of membrane were laid down. Themembrane would be fastened and tightened as usual (there could be holesalso for the tightening of a turn buckle if it were needed) then thenext roll of membrane would be laid with one side of the seam layingover the already installed cable and the other seam (which would have acable sealed within it) ready to be installed to the roof. The sidewithout a cable would be heat welded over the already installed cablefrom the prior installed roll of membrane such that the holes that wouldbe used for fastening or tightening the turn buckle could be sealedwithin and protected from the elements.

The stretched cable membrane attachment system is designed to be used oneither flat horizontal surfaces or flat vertical surfaces, such aswalls. In order to use the system on vertical surfaces, the membranewould be turned either up a wall rising above the level of the roof ordown the wall beneath the level of the roof. Then, the cable would beattached in the same manner as on a horizontal flat surface. On acompletely flat roof with no walls around it, one could turn themembrane down the wall and beneath the level of the roof then fasten thecable around the perimeter of the building to the upper part of thewall. Then, the excess membrane could be turned up such that it coveredthe cable and then heat welded or adhered to the membrane on the roof ora higher part of the building's outer wall.

In addition to using the stretched cable system for attachment of themembrane at the perimeter or interior of the roof, it is also designedto be used around roof penetrations. Typically, there is either apre-formed boot that fits around a round penetration (such as a pipe) orone might use a non-reinforced membrane that is much more pliable. Themembrane or boot is made of material that is compatible with and capableof welding to the existing reinforced membrane layer on the roof. Thismaterial comes up the side of the penetration and must be terminated andwaterproofed at this point. With the stretched cable system, the cablecould be stretched taut around round penetrations with the membranefolded over just as described previously. For square or rectangularpenetrations, the cable would be fastened or attached in the mannerpreviously described for flat surfaces. Then, either the excess portionof the membrane would then fold over the cable and be welded to thesecured section of the membrane or an additional layer of membrane couldcover the cable, thus sealing in the cable and fasteners in the samemanner as for the horizontal portions of the roof.

In the previously mentioned description, the invention has beendescribed with particular embodiments. However, those skilled in the artmay utilize other embodiments and modifications. The invention asdescribed is not limited solely to the preferred embodiments asdepicted.

1. A method and device for securing a roofing membrane to a flat or lowslope roof by means of securing a cable which consists of two endpointswhich both have a place through which a mechanical roofing fastener canbe placed and a length of cable between the two endpoints, wherein thecable is mechanically fastened over a layer of membrane and to theroofing deck or substrate and another layer of membrane is installedover the cable and its endpoints then adhered by standardnon-penetrative means to the layer of membrane beneath the cable.
 2. Themethod and device as described in claim 1 whereby the cable has a meansof connecting a turn buckle linearly along the length of the cable andbetween the two endpoints such that the act of turning the turn buckleincreases the tension of the cable when the two endpoints are secured tothe roofing substrate or decking and the turn buckle is afterward sealedby a layer of roofing membrane with the cable and its endpoints.
 3. Themethod and device as described in claim 1 whereby there exists at leastone additional fastening point within the length of the cable throughwhich a standard mechanical fastener can be used to secure the device tothe roofing substrate or decking.
 4. The method and device as describedin claim 1 whereby the cable and its endpoints are manufactured andsealed within one side of a roll of roofing membrane.
 5. The method anddevice as described in claim 1 whereby the membrane that is fastenedover the cable is material from the same roll or piece of membrane andis that excess which lies on one side of the cable which is then foldedover the cable and adhered to itself, thus sealing in the cable devicewith the single piece of membrane, which is already mechanicallyfastened to the roofing substrate or deck.